Vented test barrel assembly for revolver ammunition

ABSTRACT

A test barrel assembly for a universal receiver includes a cylinder, having a cartridge-receiving chamber, and a barrel secured to the cylinder in a manner such that a rifled bore of the barrel is in axial alignment with the chamber. Spacer means between the cylinder and barrel provides a gap of predetermined thickness therebetween and the resulting controlled venting of propellant gases through the gap during firing results in reproducible pressure and velocity readings which can be used to accurately predict actual performance of a cartridge in a revolver. Manufacture of the cylinder and barrel from a single piece of steel ensures proper alignment and uniform spacing of these parts.

' United StatesPatent n91 Bateman, Jr. et al.

[ VENTED TEST BARREL ASSEMBLY FOR REVOLVER AMMUNITION [75] Inventors: Charles H; Bateman, Jr., East Haven; Allan A. Campbell, Trumbull; James J. Capasso, Shelton, all of Conn.

[73] Assignee: Remington Arms Company, Inc.,

' Bridgeport, Conn.

22 Filed: Apr. 3,1973

21 Appl; No.: 347,381

52 us. c1. 73/167 [51] Int. Cl. G0ll 5/14v [58] Field-0f Search 73/167, 35

[56] References Cited UNITED STATES PATENTS 2.405.308 8/l946 Jack 73/167 FOREIGN PATENTS OR APPLlCATlONS Germany 73/167 497.58 1 5/1930 Germany 73/167 Primary Examiner-Donald O. Woodie] Attorney, Agent, or Firm-John H. Lewis, JrL; Nicholas Skovran [57] ABSTRACT A test barrel assembly for a universal receiver includes a cylinder, having a'cartridge-receiving chamber, and a barrel secured to the cylinder in a manner such that a rifled bore of the barrel is in axial alignment with the chamber. Spacer means between the cylinder and bar- 1 rel provides a gap of predeterminedthickness therebetween and the resulting controlled venting of propellant gases through the gap during firing results in reproducible pressure and velocity readings which can be used to accurately predict actual performanceof a cartridge in a revolver. Manufacture of the cylinder and barrel from a single piece of steel ensures proper alignment and uniform spacing of these parts.

5 Claims, 5 Drawing Figures PATENTE; .JEE] H914 3,854,331

SHEEI 10F 2 PATENTEL LEE] 3.854.331

sum 2 or 2 VENTED TES T BARREL ASSEMBLY FOR REVOLVER AMMUNITION This invention relates to ballistic measurement and more particularly to a test barrel assembly for accurately and reproducibly measuring'chamber pressure and muzzle velocity for revolver cartridges.

In the manufacture of ammunition, it is important that interior ballistic data for each type of cartridge be known. Accurate measurements of both chamber pressure and muzzle velocity must be made to determine whether the cartridge will fire safely and, additionally, how it will perform-in a gun. These readings must account for all variables affecting interior ballistics, including the caliber and type of cartridge and bullet, the type and quantity of propellant powder, and the type of primer as well as operating characteristics of the gun, such as the type of gun and the length of its barrel.

It has been determined that these measurements can be most effectively made, by utilizing a universal receiver. This is a mechanism of great structural strength which is securely mounted and simulates firing in an actual gun. Certain portions of the universal receiver are useable with all calibe rs and types of ammunition, such as the breech block, firing pin, and a firing mechanism capable of remote operation. To accommodate different cartridge types and sizes, a large number of different barrel assemblies, each having its own chamber, may be selectively attached so that the same receiver can'be used to test fire virtually any type of small arms ammunition. The replaceable barrel assembly is adapted to permit the measurement of chamber pressure by compression of a metal slug or by use of a transducer, each method being well known to those skilled in the art.

The universal receiver makes it possible to obtainreproducible pressure and velocity readings and permits variables, such as barrel length, to be controlled. Thus,

its use is much preferable to the alternative of obtaining these valuesfrom actual firearms, inasmuch as additional variables relating to the interaction of parts or defects in the gun may be introduced, thus rendering the pressureand velocity data obtained of little value or validity for any gun other thanthe one on which they were measured. 1

While the universal receiver, fitted with an appropri- I ate barrel assembly, has been able to provide appropriate ballistic data for rifles, shotguns and most hand guns, the results obtained for revolver ammunition has been virtually meaningless. Barrel assemblies available in the prior art have been unable to simulate actual firing conditions, becausein a revolver, the relationship between the revolving cylinder and the barrel results in a significant venting of propellant gases not heretofore reproducible by a test barrel assembly,

The use of actual revolvers for ballistic testing did not alleviate this problem because design differences in different revolvers result insignificant variations in the amount of gas which is vented and because the erosion of parts on a revolver with repeated use causes the amount of gas vented by each revolver to increase significantly during the life of the gun. For these reasons, it has been heretofore impossible to provide reproducible ballistic data which would apprise a revolver owner. of the pressure and velocity information required for an accurate determination of how his revolver would perform when loaded with a particular type of ammunition. Additionally,information regarding bullet mushrooming and accuracyobtained through the use of prior art test barrels has been incorrect when applied to revolvers.

In accordance with this invention, a test barrel assembly for a universal receiver has a cylinder and a barrel which are attached together with a cartridgereceiving chamber in the cylinder in axial alignment with a rifled bore of the barrel. A plurality of spacers of predetermined length are utilized-between the cylinder and barrel so that a gap of predetermined thickness is provided between the cylinder and barrel. In this manner, the firing conditions of a revolver can be satisfactorily duplicated and reproducible pressure and velocity data may be obtained which accurately predicts the performance of a particular type of ammunition in a revolver in good condition. By substituting spacers of greater length, the gap-may be increased permitting measunnent of the deterioration in the interior ballistics of a revolver, resulting from wear caused by extended use, so that performance under these conditions can also be predicted.

The cylinder and barrel are manufactured from a single piece of metal in which passages which require accurate alignment, such as the chamber and bore, are drilled prior to separation of the cylinder from the barrel. After separation, the cylinder and barrel are mounted on a mandrel which fits the exact bore dimension so that proper alignment maybe maintained during assembly.

It is an object of this invention to provide a test barrel assembly for testing revolverammunition in a universal receiver.

It is another object of thisinvention to provide a test barrel assembly for testing revolver ammunition in a universal receiver which reproduces the firing conditions in a revolver.

It is an additional object of this invention to provide a test barrel assembly for testing revolver ammunition in a universal receiver in which the thickness of a gap between the cylinder and the barrel is adjustable so that the conditions of both new and'worn revolvers can be simulated for the accurate and-reproducible measure FIG. 3 is across-sectional view of the test barrel as- I I I sembly taken generally along the line 3-3 of FIG. 2;

breech member 15 at one end, and has at. its other end a lock nut 16 for clamping to it a suitable test barrel assembly 17. The breech member 15 is operated by a handle 19. A firing-pin is mounted in the receiver and adapted to be struck by 'a hammer (not shown) which is, in turn, operated by a trigger mechanism including a lever 21 pivoted on a shaft 22 and a lever 24 pivoted on a pin 25 in a slot intermediate the ends of the lever 21-. The lever 24 has at one end an extension arranged to engage the hammer. The firing pin 20 is operated by moving the lever 21 rearwardly. This biases the hammer away from the firing pin and then releases the hammer so that it impacts the firing pin and fires the cartridge in a manner well known to those skilled in the art.

Mounted on the top of the body member 12 in an open space between a pair of wall portions 12a of the body member is a device 26 for registering the pressure developed within the barrel.

Referring now to FIGS l-4, the test barrel assembly 17 generally consists of a cylinder 27 and a barrel 29,

both preferably machined from the same piece of steel.

The cylinder 27 has a breech end portion 27a of reduced diameter and has an axial passage bored therethrough and having a proper contour and dimensions to serve as a chamber 30 for containing a cartridge to be tested. A radial passage 31 communicating with the chamber 30 maybe provided to accommodate the accommodate attachment of the cylinder to the barrel.

In the preferred embodiment, the cylinder 27 has a forward extension 27b of reduced diameter formed integrally therewith. This forward extension 27b may be on the order of 0.125 in. in length. An alignment notch 35 may be formed in the breech end of the cylinder 27 for interaction with an alignment stud 36 in the universal receiver 11 to ensure the proper orientation of the test barrel assembly 17.

The barrel 29 may be of any desired length but is preferably about 2, 4 or 6 inches in length to simulate actual revolver barrels. The barrel 29 has an enlarged attachment portion 29a at a rear end thereof. An axial passage is provided through the barrel and preferably rifled to serve as a bore '37. A plurality of passages 39 is placed over each capserew 40 in the space between the cylinder 27 and the enlarged attachment portion 29a of the barrel .29. To provide a gap of a particular thickness, spacers 41 of a particular length will be used. For example, if the space between the forward surface of the cylinder 27 and the rear surface of the enlarged attachment portion 29a of the barrel 29 is 0.250 in. without any gap between the extensions 27]) and 29!), the use of a plurality of spacers, each having a length of 0.258 in., will produce a space between the extensions 27b and 29b of 0.008 in. Clearly, a change in the length of the spacers will result in a corresponding change in the thickness of the gapv so that the venting of gases through the gap may be closely controlled and adjusted to any desired amount.

As will be readily apparent from the foregoing description, proper alignment between the barrel 29 and cylinder 27 is critical for proper functioning of the test barrel assembly 17. The chamber 30 in the cylinder 27 must be coaxial with, and bear a proper dimensional relationship to, the rifled bore 37 of the barrel 29; each of the passages 39 in the enlarged attachment portion 29a of the barrel 29 must be properly aligned and ori ented with respect to the corresponding blind bores 34 in the cylinder 27; and the facing surfaces .of the barrel and cylinder and of their extensions must maintain a parallel relationship to each other when the barrel and cylinder are attached by the cap screws 40 so that the spacers 41 may provide a uniform gap between the extensions 27b and 29b without disturbing the alignment of. the chamber 30 with the rifled bore 37. It is also desirable thatthese precise dimensional relationships be provided without excessive machining costs.

To accomplish this, the cylinder 27 and barrel 29 are both machined from a single piece of metal. A blank (see FIG. 5), preferably made of steel, is turned to have i a barrel portion 50a, which is not less than the length desired for the finished barrel 29, and an enlarged portion 50b of sufficient length to be machined into the cylinder 27 and the enlarged attachment portion29a of the barrel 29. An axial passage 51 is bored through the blank 50 and rifled and preferably has a diameter corare preferably provided in the attachment portion 29a of the barrel 29 in alignment with the corresponding blind bores 34 in the cylinder 27 so that threaded attachment means, such as a plurality of cap screws 40,-

between the forward extension 275 of the cylinder 27 and the rear extension 29b of the barrel 29. This is accomplished by the use of a plurality of spacers 41 which may be in the form of tubular cylinders, one of which responding to the dimensions of the particular caliber bullet to be tested in the finished test barrel assembly. A groove 52 is then turned in'the enlarged portion 50b of the blank 50 forming a central portion 500 of reduced diameter. A plurality ofopenings are drilled in the enlarged portion 50b of the blank 50, bridging the groove 52 and forming the passages 39 and, when tapped, the blind bores 34. After separation of the bar-.

rel and cylinder, the blind bores 34 of the cylinder 27 and the passages 39 of the barrel 29 will, without further adjustment, be properly aligned. The central porin completion of a properly aligned test barrel'assembly The assembled test barrel assembly 17, with the piston 32 removed, is inserted into the forward end of the body member 12 of the universal receiver 11 (see'FlG.

5 l proper orientation being provided by interaction of the alignment notch 35 on the cylinder 27 with the alignment stud 36 of the universal receiver. A spacer 55 is positioned in the universal receiver forwardly of the test barrel assembly 17 and the lock nut 16 is threaded into the body member 12 to firmly secure the test barrel assembly 17 in place. The piston 32 may then be inserted between the wall portions 12a into the passage 31 and the pressure measuring device 26 clamped in place. The universal receiver 11 is thus prepared for operation as soon as a revolver cartridge to be tested is inserted into the chamber 30.

When a cartridge is fired in the universal receiver 1 l, 7

extension 27b of the cylinder 27 and the rear extension 2% of the barrel 29, thus simulating the gas venting action which occurs in an actual, revolver.-These vented gases pass through the space between the wall portions 12a of the body member 12 and thus encounter no back pressure which would result in erroneously high readings. Because the barrel 29 is made the same length as the gun for which ballistic readings are to be determined and the gap is made to conform to that of the gun type, meaningful pressure and velocity readings can be obtained for revolver ammunition. By changing the spacers 41 to increase the thickness of the gap, the venting of gases through the gap can be increased to simulate the effects on internal ballistics of excessive gun wear.

Significance of the use of the test barrel assembly 17 of this invention can be clearly demonstrated by a comparison of ballistic measurements. For example, in firing tests wherein velocities were measured in 6 in. barrels for 0.38 Special cartridges having lead bullets, the velocity measured for a cartridge with a'l58 grain bullet, when fired in a standard unvented test barrel, of the type approved and used by the Sporting Arms and Ammunition Manufacturers Institute (SAAMI), was 875 ft./sec. When fired in a test barrel assembly made in accordance with this invention and having a gap between the cylinder and barrel of 0.008 in., the velocity was measured at 780 ft./sec. Thus, the measurement with the SAAMI unvented test barrel was about 12.2 percent higher than the velocity which would result from firing the cartridge in an actual revolver. In another test utilizing a 200 grain bullet,. the unvented test barrel produced a velocity reading of 760 ft./sec. while the vented test barrel of this invention produced a reading of 675 ft./sec. In this case, the use of the unvented bargases are vented through the gap between the forward rel resulted in a velocity reading which was 12.6 percent high. In other tests, velocitiesin excess of 15 perheavily fired revolvers, and further readings weretaken. Cartridges which produced readings of 920 ft./sec. and 930 ft./sec. with the gap set at 0.008 in., were found to produce velocity readings of 822 ft./sec. and 784 ft./sec., respectively, when the gap was increased to 0.020 in. These figures represent velocity decreases of 10.6 percent and 15.7 percent, respectively.

We claim:

1. A test barrel assembly for a universal receiver having cartridge firing means, said test barrel assembly comprising a cylinder having a single chamber for receiving a cartridge and having a forward end, a barrel of predetermined length havinga longitudinal bore and having a rear end, attachment means for securing said cylinder to said barrel with said chamber and said bore in axial alignment, and spacer means for producing a gap of predetermined thickness between the forward end of said cylinder and the rear end of said barrel.

2. The test barrel assembly of claim 1 wherein said.

attachment means comprises a plurality of threaded fasteners and said spacer means comprises a tubular spacer positioned on each of the threaded fasteners be- .tween said cylinder and said barrel.

' of said cylinder and the rear end of said barrel, and second spacer means for producing a gap of a second thickness, different from said first thickness between the forward end of said cylinder and the rear end of said barrel, and means for selectively mounting said first spacer means or said second spacer means between said cylinder and said barrel.

Dedication 3,854,331.0harles H. Bateman, J12, East Haven, Allan A. Campbell, Trumbull, and James J. Uapasso, Shelton, Conn. VENTED TEST BAR- REL ASSEMBLY FOR REVOLVER AMMUNITION. Patent dated Dec. 17 1974:. Dedication filed July 28, 1975, by the assignee, Remington Aams Company, I nc. Hereby dedicates the remaining term of said patent to the Public.

[Ofiioz'al Gazette Decembea' 16, 1975.] 

1. A test barrel assembly for a universal receiver having cartridge firing means, said test barrel assembly comprising a cylinder having a single chamber for receiving a cartridge and having a forward end, a barrel of predetermined length having a longitudinal bore and having a rear end, attachment means for securing said cylinder to said barrel with said chamber and said bore in axial alignment, and spacer means for producing a gap of predetermined thickness between the forward end of said cylinder and the rear end of said barrel.
 2. The test barrel assembly of claim 1 wherein said attachment means comprises a plurality of threaded fasteners and said spacer means comprises a tubular spacer positioned on each of the threaded fasteners between said cylinder and said barrel.
 3. The test barrel assembly of claim 1 including pressure responsive means in said cylinder for measuring pressure in said chamber.
 4. The test barrel assembly of claim 1 wherein said cylinder and said barrel are manufactured from a single piece of metal.
 5. The test barrel assembly of claim 1 wherein said spacer means comprises first spacer means for producing a gap of a first thickness between the forward end of said cylinder and the rear end of said barrel, and second spacer means for producing a gap of a second thickness, different from said first thickness between the forward end of said cylinder and the rear end of said barrel, and means for selectively mounting said first spacer means or said second spacer means between said cylinder and said barrel. 